The objectives of this proposal are 1) to study the natural history of pulmonary vascular injury induced by oleic acid in the dog lung, 2) to study the effect of oxygen therapy on the natural history of this injury, and 3) to determine the relationship of pulmonary blood flow to the rate of development, magnitude, and resolution of pulmonary edema due to vascular leak in this model. Studies will be conducted in unanesthetized dogs chronically instrumented for measurement of right and left heart vascular pressures, cardiac output, and arterial and mixed venous blood gases. The course of oleic acid pulmonary vascular injury from time of injury to time of resolution will be followed in air breathing and oxygen breathing animals and in animals who have had their cardiac output chronically increased by arteriovenous fistula. Gas exchange and circulatory variables will be measured every 24-hours until resolution of the acute process. Groups of animals will be sacrificed at 24-hour intervals after injury for gravimetric measurement of lung water and histologic study.